RIS stands for remote installation services. You save the installed image on a windows server and then we use RIS to install the configured on in the new hardware. We can use it to deploy both server and client OS. Imaging or ghosting also does the same job of capturing an installed image and then install it on a new hardware when there is a need.

We go for RIS or i am going/ghosting because installing OS every time using a CD can be a very time consuming task. So to save that time we can go for RIS/Ghosting/imaging.